In the prior art, a number of devices have employed gauges or charts in order to assist the fisherman in determining the depth of his line. For example, U.S. Pat. No. 3,149,419 to Koznarski which teaches a trolling aid that employs a graph board having angle markings, a line length scale, a resultant lure depth chart, and a line guide at the origin of the graph board. The board clamps to the boat, while a weighted mechanism keeps the graph board plumb. Another depth determining device is taught in U.S. Pat. No. 2,669,785 to Rydzewski, which discloses a device for tracking the bottom of a lake. The device is clamped to the boat and has scales that measure the angle of an extending line in order to determine depth. A pole-mounted device is taught in U.S. Pat. No. 3,874,108 to Connor. This apparatus includes both a line length measuring meter and an angle gauge. From the combined information of these two, lure depth is determined from a chart. U.S. Pat. No. 3,959,885 to Edmiston discloses an angle gauge that clips onto the end of a fishing pole. From simple angle information, Edmiston points out that a quick trigonometric calculation can produce an idea of the depth, and that a chart could be printed on the device. A line guide is included to assure that the proper angle is indicated. U.S. Pat. No. 4,586,286 to Cheatham, Jr., discloses another device for controlling the depth of a lure during trolling, but from an outrigger and boom. A spirit level allows horizontal leveling, while drag from the line influences an angle measuring device on a rotatable part of the boom. U.S. Pat. No. 2,089,031 to MacDonald shows a metering or measuring gauge for the length of line extended from a reel. U.S. Pat. No. 2,752,686 to Anderson shows a similar gauge on a reel and, in addition, discloses the use of this information for adjusting trolling depth.
The desirability of having available a depth determining gauge is clear from the variety of instruments proposed in the prior art for this purpose. However, it appears that no one instrument has been entirely satisfactory. One possible problem in the prior art is complexity and resultant difficulty in use. Devices that clamp onto a boat can be awkward to install and use. Gauges that are built into a reel can be expensive and lack flexibility when a different reel or pole is to be used. Consequently, it would be desirable to have available a depth gauge that is small in size, highly portable, easily installed, and simple to use. In addition, it would be highly desirable for such an instrument to be adaptable to almost any type of fishing equipment. Further benefits would arise from low cost and durable construction, having no moving parts.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the fishing depth gauge and method of use of this invention may comprise the following.